The invention relates to a gas laser. Such a laser tube is described in U.S. Pat. No. 3,988,698.
In a known laser design a cylindrical glass jacket equipped with metallic end plates encloses a glass capillary and a hollow, cold cathode. The capillary has a flared end, at which it is fused to the glass jacket and one end plate; the other cathode end--projecting slightly into the cathode cavity--is kept in place by a supporting spring pushed over it. This spring is pushed against a circular jacket constriction by the cathode which in turn is sprung against the other end plate by an elastic lead.
Such a laser is relatively easy to assemble and also quite rugged mechanically. However, in the event of severe jarring the supporting spring may be driven out of its original position and remain dislodged, assuming a new position in which it slightly tips the axis of the capillary. The reflectors are then no longer optimally alignd, with the consequence that the laser performance declines. Such misalignments could largely be avoided by making the tolerances of the affected parts and surfaces very close; but this would be a considerable burden on production.
A particularly shockproof design results from replacing the spring by a glass disc, such as provided in the U.S. Pat. No. 3,904,986, and soldering or fusing this disc to the capillary and to the jacket. This design has not been used because the cost is too high and the resonator may become detuned due to thermal distortions.
It has also been proposed to clamp the free end of the capillary by a glass or metal nipple emanating from the adjacent end plate (see DE-OS No. 30 37 153 or U.S. Pat. No. 4,352,185). Such a mounting can stand even hard knocks and allows for thermal expansion differences. However, the capillary cannot be utilized over its entire length, it tends to vibrate and sag, and that most likely must communicate with the ballast chamber through a side opening, which renders ignition more difficult.
The object of the invention is to provide a gas laser which is of simple design and performs with consistancy even under great mechanical and thermal stresses in a temperature range from 20.degree. C. to 300.degree. C.